A nominal response model-based computerized adaptive testing procedure (nominal CAT) was implemented using simulated data. Ability estimates from the nominal CAT were compared to those from a CAT based upon the three-parameter logistic model (3PL CAT). Furthermore, estimates from both CAT procedures were compared with the known true abilities used to generate the simulated data. Results showed that the nominal CAT's ability estimates were highly correlated with those of the 3PL CAT as well as with the true abilities. Furthermore, the nominal CAT had a significantly higher association with negative true thetas than did the 3PL CAT, and it also had significantly lower standard errors of estimate than did the 3PL CAT. However, the nominal model-based CAT had difficulty estimating positive thetas and had a poor convergence rate. In contrast, the 3PL CAT had a high convergence rate and its performance was not affected by whether the true abilities were positive or negative. Potential reasons for the nominal CAT's high nonconvergence rate as well as implications for computerized adaptive testing were discussed. (Author)